Sealing Assembly Deposition on Forming Drum

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Solution Overview

Problem

The polymeric sealing material used in self-sealing tires is difficult to handle due to its poor consistency and high adhesiveness, leading to issues during transportation, cutting, and application, resulting in instability and increased chances of errors during tire production, which affects productivity and quality.

Innovation Solution

A method involving a sealing assembly with a self-supporting thermoplastic film and polymeric sealing material, where the assembly is unwound, cut to size, and deposited onto a forming drum using a controlled process that includes locking the leading end with a locking bar and rotating the drum to overlap the trailing end, ensuring precise and repeatable deposition without jamming or displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymeric sealing material is used in self-sealing tyres, then air loss prevention is improved, but handling difficulty increases due to poor consistency and high adhesiveness

Engineering Contradiction:

Improveair loss preventionVSAvoidhandling difficulty

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

A release film is introduced as an intermediary between the polymeric sealing material and the handling equipment. The release film has low adhesion to the polymeric material, allowing easy separation during handling, cutting, and application operations while maintaining the sealing material's effectiveness in preventing air loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The polymeric sealing material is configured as a thin film layer supported by a thermoplastic polymer layer. This thin film structure reduces the material's rigidity and improves flexibility, making it easier to handle, cut, and apply while maintaining its sealing functionality.

Inventive Principle:

Principle #30Flexible shells and thin films

2Manufacturing precision

If polymeric sealing material is deposited on forming drum, then sealing assembly is created, but deposition control is difficult due to material instability

Engineering Contradiction:

Improvedeposition controlVSAvoidmaterial instability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The release film acts as a mediator during the deposition process, providing a stable interface between the unstable polymeric sealing material and the forming drum. This allows for precise control of the sealing assembly's position and orientation during deposition while the material maintains its required instability for sealing performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing assembly is prepared in advance with the polymeric sealing material already positioned on the release film before reaching the forming drum. This preliminary preparation ensures correct positioning and reduces the complexity of controlling deposition during the actual tire manufacturing process.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If sealing assembly is handled during transportation and cutting, then tire production progresses, but material deforms or tears due to high adhesiveness

Engineering Contradiction:

Improveproduction progressVSAvoidmaterial integrity

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The release film serves as a protective intermediary during transportation and cutting operations. It prevents the highly adhesive polymeric sealing material from sticking to handling equipment and other surfaces, thereby preventing deformation and tearing while enabling smooth production progress.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If sealing assembly is made thin and slippery for ease of handling, then operation ease is improved, but dimensional stability decreases

Engineering Contradiction:

Improvehandling easeVSAvoiddimensional stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The release film provides dimensional stability during handling operations while allowing the thin, slippery sealing assembly to maintain its ease of operation characteristics. The release film's friction properties enable controlled handling without compromising the sealing material's low-friction surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2790909B1Method for controlling deposition of a layer of sealing polymeric material on a forming drum and process for producing self-sealing tyres for vehicle wheels

Publication Date: 2016.08.24 PIRELLI TYRE SPA

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AI summary

In a process for producing self-sealing tyres for vehicle wheels, a continuous sealing assembly (12) comprising a self-supporting thermoplastic film (11) and a layer of polymeric sealing material (10) is unwound from a reel holder (19) on which is stocked, separated by a protective film (20) associated to the layer of polymeric sealing material (10), cut to size and then wound around a forming drum (14). Winding the sealing assembly (12) cut to size comprises: feeding the sealing assembly (12) cut to size onto a chute (P1) from top to bottom up to the forming drum (14); depositing a leading end (12a) of the sealing assembly (12) cut to size on a radially outer surface (14a) of the forming drum (14); locking the leading end (12a) on the forming drum (14) by means of a locking bar (44); setting the forming drum (14) in rotation with the locking bar (44) dragging the sealing assembly (12) cut to size and winding it on the forming drum (14) up to overlapping and sealing a trailing end (12b) of the sealing assembly (12) cut to size on the leading end (12a).